Credit: Courtesy the Second City

Started on the north side in 1959, the Second City has become one of America’s great comedy theaters, with a long list of illustrious alumni, an Emmy-award winning TV series (SCTV), and a combined current enrollment of more than 3,000 students looking to be the next Colbert or Fey at training centers here and in Hollywood and Toronto.

The organization is celebrating its 50th anniversary this weekend with performances, panel discussions, and screenings, highlighted by The Second City Alumni: One Night Only—”classic scenes from The Second City archives” performed live by the likes of Steve Carell, Harold Ramis, Jim Belushi, Nia Vardalos, Bob Odenkirk, George Wendt, Jeff Garlin, Fred Willard, Horatio Sanz, and many others (Sat 7 PM, $125).

More big names will be on hand for SCTV Reunion, two shows of live sketch comedy from members of the series’ original cast, including Joe Flaherty, Eugene Levy, Andrea Martin, Catherine O’Hara, Ramis, Martin Short, Dave Thomas, and “special guests” (Fri 12/11, 7 and 10 PM, $175-$750).

More highlights:

A panel discussion on The Colbert Report, featuring Stephen Colbert (Sat 12/12, 10 AM, $25). The First Cast, a panel discussion with Alan Arkin, Mina Kolb, and Paul Sands that includes clips from a 1961 show (Sat 12/12, 10 AM, $15). The Jeff Garlin Combo Platter, a live performance featuring Garlin, Willard, and Robert Klein (Sat 12/12, 2 PM, $25). Women Fully Clothed, live performances by female Toronto alumni including Robin Duke (Sat 12/12, 8 PM, and Sun 12/13, 2 PM, $25). All Girl Revue, LA-based women in live performances (Sat 12/12, 10 PM, and Sun 12/13, 4 PM, $20). A screening of a new documentary, Improv Legends (Sun 12/13, noon, $10). From the Vault, a “mixed bag ” of rare show footage (Sun 12/12, 2 PM, $10). Second City in the Sixties, a panel including Arkin, Willard, Klein, Kolb, Bernie Sahlins, Sheldon Patinkin, and David Steinberg (Sun 12/13, 4 PM, $25).

Second City also hosts The Second City That Never Sleeps: Letters to Santa 2009—a 24-hour improv and music event that benefits needy kids. (Tue 12/15, 6 PM, through Wed 12/16, 6 PM, Pipers Alley, 1608 N. Wells, $15 with a cash bar). The schedule includes Jeff Tweedy (7 PM), Robbie Fulks (10 PM), Upright Citizens Brigade’s Asssscat with Matt Walsh, Sanz, and Chicago friends (midnight), Flashmob Marching Band (3 AM), Bonnie Prince Billy (6 AM), BabyCo (7:30 AM), Nina Nastasia (noon), the Mountain Goats (2 PM), and the Blisters (4:30 PM).

Unless otherwise noted, all events take place on various stages at Second City, 1616 N. Wells, 312-337-3992,